Thermoplastic resin composition, polymer composition, and molded object obtrained from the composition

ABSTRACT

A thermoplastic resin composition (Y) characterized by comprising (A) 20 to 64.9 wt % one or more ethylene copolymers comprising an ethylene/α-olefin copolymer, (B) 35 to 70 wt % metal hydroxide, and (C) 0.1 to 30 wt % grafted ethylene polymer. The resin composition has excellent flame retardancy and has satisfactory pliability/flexibility and excellent tensile properties. It is suitable for use as an insulating material or sheath for electric wires. Also provided are: a polymer composition (Z) having high flame retardancy, characterized by comprising relative to (AA) 100 parts by weight of a polymer such as a thermoplastic polymer or thermosetting polymer, in the ratio of (BB) 50 to 250 parts by weight of a metal hydroxide, (E) 0.1 to 40 parts by weight of a triazine ring containing compound, and (F) 0.1 to 40 parts by weight of a polyhydric alcohol; and a molded object obtained from the polymer composition. These are suitable for use as an insulating material or sheath for electric wires.

TECHNICAL FIELD

The present invention relates to a thermoplastic resin composition and amolded article thereof and in particular to a thermoplastic resincomposition suitable as an insulating material or sheath material forelectric wires and a polymer composition of high flame retardancy and toa molded article comprising the same.

BACKGROUND ART

Conventionally, a sheath material and a partially insulating materialfor electric wires often make use of polyvinyl chloride (PVC), and itsflexibility, flame retardancy and insulating properties have beenappraised. Generally, PVC contains a large amount of plasticizer so thatwhen the plasticizer is lost by heating etc., the PVC is easily hardenedand generates a chlorine-based gas upon combustion, and thus developmentfor electric wires which can be substituted for PVC has been desired inrecent years.

Under these circumstances, various flame-retardant resin compositionsbased on ethylene-based polymers such as polyethylene have beenproposed.

U.S. Pat. No. 6,232,377 describes a flame-retardant resin compositionwhich comprises a specific ethylene-based copolymer selected from anethylene/vinyl ester copolymer, an ethylene/α,β-unsaturated carboxylicacid copolymer and low-density polyethylene, and further comprises ametal hydroxide, a triazine ring containing compound and a specificflame-retardant compound. However, these ethylene-based polymers have aproblem that pliability and flexibility are easily lowered when theamount of inorganic compounds such as metal oxides is increased in orderto increase the flam retardant effect.

Accordingly, a first object of the present invention is to provide aresin composition excellent in pliability and flexibility and superiorin tensile physical properties, a molded product comprising the same,particularly an insulating material and/or sheath for electric wires.

On one hand, many kinds of thermoplastic polymers and thermosettingpolymers have been used in internal wires in home appliances, buildings,interior decorations, automobile parts, and electronic instruments. Amajority of these polymers (particularly olefin polymers) are easilyflammable.

From the viewpoint of protection against disasters, there is increasingdemand for incombustibility and flame retardancy of various facilitiesand structures, and particularly high flame retardancy is required ofhome appliances that can be the origin of a fire. Criteria for flameretardancy of internal wire materials are stipulated by for example ULstandards in the US (Underwriters' Laboratories Inc.) etc., andevaluated by a vertical flame test called VW-1 test. Accordingly,materials usable for a long time even exposure to high temperatures andfires are desired, and a method of conferring high flame retardancy onmany thermoplastic polymers and thermosetting polymers by adding a flameretardant in production of the polymers or in production of moldedproducts is widely used.

As the flame retardant, many compounds such as metal hydroxides,borates, organic halogenated compounds, phosphorus compounds such asphosphates, red phosphorus, organic phosphorus compounds etc. andorganic nitrogen compounds are used. Among these, organic halogenatedcompounds, organic phosphorus compounds etc. exhibit an excellent flameretardant effect.

However, these halogen-containing compounds have a problem that they arepyrolyzed at the time of molding resin to generate hydrogen halide, todeteriorate the resin itself thus causing coloration, or to generatehydrogen halide on the occasion of a fire.

As a halogen-free flame retardant, an inorganic flame retardant such asaluminum hydroxide, magnesium hydroxide or the like is conventionallyused. When only the inorganic compound is used, however, the flameretardant effect is low, and a large amount of the flame retardant isrequired to exhibit a sufficient effect, but when it is added in a largeamount, physical properties inherent in resin may be deteriorated, andthus its application is limited.

As halogen-free flame-retardants exhibiting a relatively excellent flameretardant effect, there are specific organic phosphorus compounds andspecific organic nitrogen compounds, and these are also oftenpractically used.

The conventional organic phosphate flame retardant is represented bytriphenyl phosphate (referred to hereinafter as “TPP”), but thiscompound is poor in heat resistance and highly volatile, and is thus notsuitable for resin to be molded at high temperatures, and particularlybecause of pollution of a molding die, its application is limited.

As compounds used as flame retardants hardly volatilizing organicphosphorus, there are condensed phosphates described in JP-B 51-19858,JP-A 59-202240 etc. These compounds are superior to TPP in respect ofheat resistance and low volatilization, but do not surpass TPP in flameretardant effect per unit weight of phosphorus, and therefore there is aproblem that these should thus be added in a large amount, and thus thetemperature of thermal deformation is significantly lowered due to theeffect of the plasticizer for resin.

A large number of compositions using flame-retardants based on condensedpolyphosphates such as ammonium polyphosphate and polyphosphoric amidesare also proposed (JP-A54-22450, JP-A 9-316250 etc.). However,polyphosphoric acid absorbs water to reduce electrical resistancegradually due to water absorption and is thus not suitable as aninsulating covering material for electric wire/cable etc., and thereforeits application is limited.

To prevent nutrient enrichment in closed water systems in lakes andmarshes, compositions substituted for phosphorus flame-retardants arealso required in recent years.

Organic nitrogen compounds such as melamine also exhibit a relativelyhigh flame retardant effect (JP-A 8-176343 etc.). However, thesecompounds have been often used in combination with the phosphorus flameretardant in order to achieve a higher flame retardant effect.

Accordingly, a second object of the present invention is to provide apolymer composition having high flame retardancy without containing ahalogen- or phosphorus-based flame retardant, particularly a flameretardant polymer composition suitable as a covering material or sheathfor electric wires.

DISCLOSURE OF INVENTION

The thermoplastic resin composition (Y) according to the presentinvention comprises:

-   -   (A) 20 to 64.9 wt % ethylene copolymer comprising (A-1) an        ethylene/α-olefin copolymer consisting of ethylene and C3 to C10        α-olefin and (A-2) an ethylene polymer other than (A-1) in such        a ratio that (A-1)/(A-2) is 20/80 to 100/0 by weight,    -   (B) 35 to 70 wt % metal hydroxide, and    -   (C) 0.1 to 30 wt % graft-modified ethylene polymer.

In the thermoplastic resin composition (Y), it is preferable that thegraft-modified ethylene polymer (C) is a graft-modified product ofunsaturated carboxylic acid or a derivative thereof.

In the thermoplastic resin composition (Y), it is preferable that thegraft-modified ethylene polymer (C) is a graft-modified product ofunsaturated carboxylic acid or a derivative thereof wherein the amountof the graft is 0.01 to 10 wt %.

In the thermoplastic resin composition (Y), it is preferable that theethylene polymer before modification of the graft-modified ethylenepolymer (C) of unsaturated carboxylic acid or a derivative thereof is anethylene/α-olefin copolymer consisting of ethylene and C3 to C10α-olefin, and the ethylene polymer before modification has the followingproperties:

-   -   (i) the density (ASTM D1505, 23° C.) is in the range of 857 to        890 kg/m³,    -   (ii) the melt flow rate (MFR₂) (ASTM D1238, loading 2.16 kg,        190° C.) under a loading of 2.16 kg at 190° C. is in the range        of 0.1 to 20 g/10 min., and    -   (iii) the index (Mw/Mn) of molecular-weight distribution        evaluated by GPC is in the range of 1.5 to 3.5.

In the thermoplastic resin composition (Y), it is preferable that theethylene/α-olefin copolymer (A-1) has the following properties:

-   -   (i) the density (ASTM D1505, 23° C.) is in the range of 855 to        910 kg/m³,    -   (ii) the melt flow rate (MFR₂) (ASTM D1238, loading 2.16 kg,        190° C.) under a loading of 2.16 kg at 190° C. is in the range        of 0.1 to 100 g/10 min., and    -   (iii) the index (Mw/Mn) of molecular-weight distribution        evaluated by GPC is in the range of 1.5 to 3.5.

In the thermoplastic resin composition (Y), it is preferable that theethylene/α-olefin copolymer (A-1) has the following properties:

-   -   (i) the density (ASTM D1505, 23° C.) is in the range of 857 to        890 kg/m³,    -   (ii) the melt flow rate (MFR₂) (ASTM D1238, loading 2.16 kg,        190° C.) under a loading of 2.16 kg at 190° C. is in the range        of 0.1 to 20 g/10 min., and    -   (iii) the index (Mw/Mn) of molecular-weight distribution        evaluated by GPC is in the range of 1.5 to 3.5,    -   (iv) the B value determined from ¹³C-NMR spectrum and the        following equation is 0.9 to 1.5;        B value=[POE]/(2·[PE][PO])        wherein [PE] is the molar fraction of a structural unit derived        from ethylene in the copolymer, [PO] is the molar fraction of a        structural unit derived from α-olefin in the copolymer, and        [POE] is the ratio of the number of ethylene/α-olefin chains to        the number of all dyad chains in the copolymer.

The polymer composition (Z) of the present invention preferablycomprises:relative to

-   -   (AA) 100 parts by weight of at least one polymer selected from a        thermoplastic polymer (aa1) and a thermosetting polymer (aa2),        in the ratio of    -   (BB) 50 to 250 parts by weight of a metal hydroxide,    -   (E) 0.1 to 40 parts by weight of a triazine ring containing        compound, and    -   (F) 0.1 to 40 parts by weight of a polyhydric alcohol.

In the polymer composition (Z), it is preferable that the thermoplasticpolymer (aa1) is an ethylene polymer.

In the polymer composition (Z), it is preferable that the weight ratioof the polyhydric alcohol (F) to the triazine ring containing compound(E) is in the range of the following relationship (1):(F)/(E)≧1  (1)

The molded product of the present invention comprises the thermoplasticpolymer (Y) or the polymer composition (Z).

In the present invention, the molded product is preferably an insulatingmaterial for electric wires. The molded product is preferably a sheathfor electric wires.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a perspective view of a partially cut section of a VW-1 flametest device prescribed in the UL standards. In FIG. 1, 1 is a chamber, 2is an insulating electric wire, 3 is a kraft paper, 4 is absorbentcotton, and 5 is a burner. In FIG. 1, length a is 10 inches, length b is17 inches, length c is 3 inches, distance d is 1.5 inches, angle θ1 is70°, and angle θ2 is 20°.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the thermoplastic resin composition (Y), polymercomposition (Z), and a molded product comprising the composition, andits applications are specifically described.

[Thermoplastic Resin Composition (Y)]

The thermoplastic resin composition (Y) according to the presentinvention comprises:

-   -   (A) 20 to 64.9 wt % ethylene copolymer comprising (A-1) an        ethylene/α-olefin copolymer consisting of ethylene and C3 to C10        α-olefin and (A-2) an ethylene polymer other than (A-1) in such        a ratio that (A-1)/(A-2) is 20/80 to 100/0 by weight,    -   (B) 35 to 70 wt % metal hydroxide, and    -   (C) 0.1 to 30 wt % graft-modified ethylene polymer.        [(A) Ethylene Copolymer]

The ethylene copolymer of the present invention comprises theethylene/α-olefin copolymer (A-1) and the ethylene polymer (A-2) otherthan (A-1) in such a ratio that (A-1)/(A-2) is 20/80 to 100/0,preferably 50/50 to 100/0, still more preferably 70/30 to 100/0 byweight. (A-1) and (A-2) constituting the ethylene copolymer (A) in thepresent invention may be contained in the thermoplastic resincomposition (Y), and compositions may be first produced from (A-1) and(A-2) respectively and then used to produce the thermoplastic resincomposition (Y), or (A-1) and (A-2) may be added separately in producingthe thermoplastic resin composition (Y).

[(A-1) Ethylene/α-Olefin Copolymer]

The ethylene/α-olefin copolymer (A-1) used in the present invention is acopolymer consisting of ethylene and C3 to C10 α-olefin. The C3 to C10α-olefin is specifically propylene, 1-butene, 1-pentene, 1-hexene,3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene,4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pentene,4-ethyl-1-hexene 1-octene, 3-ethyl-1-hexene, 1-octene, 1-decene, etc.The copolymer is composed of ethylene and one or more of these olefins.Among these olefins, at least one of propylene, 1-butene, 1-hexene, and1-octene is preferably used.

With respect to the content of each structural unit in theethylene/α-olefin copolymer, it is preferable that the content of astructural unit derived from ethylene is usually 75 to 95 mol %,preferably 80 to 95 mol %, and the content of a structural unit derivedfrom at least one compound selected from C3 to C10 α-olefins is usually5 to 25 mol %, preferably 5 to 20 mol %.

The ethylene/α-olefin copolymer (A-1) used in the present inventionpreferably has the following properties:

-   (i) the density is 855 to 910 kg/cm³, preferably 857 to 890 kg/m³,-   (ii) the melt flow rate (MFR₂) under a loading of 2.16 kg at 190° C.    is in the range of 0.1 to 100 g/10 min., preferably 0.1 to 20 g/10    min.,-   (iii) the index (Mw/Mn) of molecular-weight distribution evaluated    by GPC is in the range of 1.5 to 3.5, preferably 1.5 to 3.0, more    preferably 1.8 to 2.5,    more preferably-   (iv) the B value determined from ¹³C-NMR spectrum and the following    equation is 0.9 to 1.5, preferably 1.0 to 1.2;    B value=[POE]/(2·[PE][PO])    wherein [PE] is the molar fraction of a structural unit derived from    ethylene in the copolymer, [PO] is the molar fraction of a    structural unit derived from α-olefin in the copolymer, and [POE] is    the ratio of the number of ethylene/α-olefin chains to the number of    all dyad chains in the copolymer.

This B value is an indicator indicating the state of distribution ofethylene and C3 to C10 α-olefin in the ethylene/α-olefin copolymer, andcan be determined on the basis of reports of J. C. Randall(Macromolecules, 15, 353 (1982)) and J. Ray (Macromolecules, 10, 773(1977)).

A higher B value indicates that a block chain of the ethylene orα-olefin copolymer is shorter, the distribution of ethylene and α-olefinis more uniform, and the distribution of the copolymer rubbercomposition is narrower. When the B value is lower than 1.0, theethylene/α-olefin copolymer tends to have a broader composition todeteriorate handling properties.

-   (v) The intensity ratio (Tαβ/Tαα) of Tαβ to Tαα in ¹³C-NMR spectrum    is 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less.    Tαα and Tαβ in ¹³C-NMR spectrum each indicates a peak intensity of    CH₂ in a structural unit derived from C3 or more α-olefin, and means    two kinds of CH₂ different in position to the tertiary carbon, as    shown below:

Such Tαβ/Tαα intensity ratio can be determined in the following manner.A ¹³C-NMR spectrum of the ethylene/α-olefin copolymer is measured forexample by JEOL-GX270 NMR measuring instrument manufactured by JEOL,Ltd. A mixed solution of hexachlorobutadiene/d6-benzene (2/1) (volume byratio) regulated at a sample concentration of 5 wt % is measured at 67.8MHz at 25° C. with d6-benzene (128 ppm) as standard. The measured¹³C-NMR spectrum is analyzed according to Lindemann Adams' proposal(Analysis Chemistry, 43, p. 1245 (1971)) and J. C. Randall (ReviewMacromolecular Chemistry Physics, C29, 201 (1989)) to determine theTαβ/Tαα density ratio.

The ethylene/α-olefin copolymer of the present invention having not onlythe above properties but also the following property is also preferablyused.

-   (vi) The ratio [MFR₁₀/MFR₂] of the melt flow rate (MFR₁₀) at 190° C.    under a loading of 10 kg to the melt flow rate (MFR₂) at 190° C.    under a loading of 2.16 kg satisfies the following relationships:    MFR ₁₀ /MFR ₂≧5.7    Mw/Mn+4.7≦MFR ₁₀ /MFR ₂

When MFR₁₀, MFR₂, and Mw/Mn do not satisfy the above relationships,moldability and/or material strength may be lowered.

[Method of Producing the Ethylene/α-Olefin Copolymer (A-1)]

The ethylene/α-olefin copolymer (A-1) can be produced by copolymerizingethylene with at least one C3 to C10 α-olefin in the presence of ametallocene catalyst or a Ziegler catalyst consisting of a V compoundand an organoaluminum compound, and the metallocene catalyst ispreferably used.

The metallocene catalyst may be formed from a metallocene compound (a),an organoaluminum oxy compound (b) and/or a compound (c) forming an ionpair by reacting with the metallocene compound (a), or may be formedfrom (a), (b) and/or (c) and an organoaluminum compound (d).Copolymerization of ethylene/α-olefin can be carried out in the presenceof the above catalyst, usually in a liquid phase using a hydrocarbonsolvent by a batch, semi-batch or continuous method. When themetallocene catalyst comprising the metallocene compound (a) and theorganoaluminum oxy compound (b) or the ionized ionic compound (c) isused, the concentration of the metallocene compound (a) in thepolymerization system is usually 0.00005 to 0.1 mmol/L (polymerizationvolume), preferably 0.0001 to 0.05 mmol/L. The organoaluminum oxycompound (b) is supplied in an amount of 1 to 10000, preferably 10 to5000, in terms of the molar ratio of aluminum atom to the transitionmetal in the metallocene compound in the polymerization system. Theionized ionic compound (c) is supplied in an amount of 0.5 to 20,preferably 1 to 10, in terms of the molar ratio of the ionized ioniccompound (c) to the metallocene compound (a) (ionized ionic compound(c)/metallocene compound (a)) in the polymerization system. When theorganoaluminum compound is used, it is used in an amount of usually 0 to5 mmol/L (polymerization volume), preferably about 0 to 2 mmol/L.

The copolymerization reaction is carried out usually at a reactiontemperature of −20° C. to 150° C., preferably 0 to 120° C., morepreferably 0 to 100° C. and at a pressure of 0 to 7.8 MPa (80 kgf/cm²,gauge pressure), preferably 0 to 4.9 MPa (50 kgf/cm², gauge pressure).

Ethylene and α-olefin are supplied in such an amount that theethylene/α-olefin copolymer (A-1) having the above specific compositionis obtained. In copolymerization, a molecular-weight regulator such ashydrogen can also be used.

[Ethylene Polymer (A-2)]

The ethylene polymer (A-2) used in the present invention is an ethylenepolymer other than (A-1), and includes linear low-density polyethylene,high-pressure low-density polyethylene, an ethylene/vinyl acetatecopolymer, an ethylene/ethyl acrylate copolymer, an ethylene/methylmethacrylate copolymer, an ethylene/acrylic acid copolymer, anethylene/methacrylic acid copolymer and an ionomer thereof, anethylene/methacrylate copolymer, and an ethylene/C3 to C20α-olefin/non-conjugated polyene copolymer. (A-2) is preferably anethylene copolymer other than (A-1).

The ethylene copolymer (A) used in the present invention may besilane-grafted.

The silane-grafted ethylene copolymer (A) is prepared by using a vinylsilane compound in combination with a peroxide to promote silanegrafting. In the present invention, the silane-grafted ethylenecopolymer (A) can also be obtained by melt-mixing silane-ungraftedethylene copolymer (A), metal hydroxide (B), a graft modified ethylenepolymer (C) of unsaturated carboxylic acid or a derivative thereof, avinylsilane compound, and a peroxide by various conventionally knownmethods. The resulting thermoplastic resin composition according to thepresent invention contains the formed silane-grafted ethylene copolymer(A).

Examples of the vinysilane compound includeγ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane,vinyltriethoxysilane, vinyltributoxysilanevinyltris(β-methoxyethoxysilane), vinyltriacetoxysilane,methyltrimethoxysilane etc. Preferably among these areγ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, andvinyltriethoxysilane. The vinylsilane compound is used in an amount ofusually 0.5 to 2.5 wt %, preferably 0.5 to 2 wt %, relative to the totalamount (=100 wt %) of (A), (B) and (C). In other words, the vinylsilanecompound is used in an amount of usually 0.5 to 2.5 parts by weight,preferably 0.5 to 2 parts by weight, relative to the total amount (=100parts by weight) of (A), (B) and (C). When the vinylsilane compound isused in the above ratio, the rate of silane grafting is high, and asuitable degree of silane grafting is obtained, resulting in a moldedproduct excellent in balance between tensile elongation and tensilebreak strength, for example a covering layer for electric wires.

In the present invention, the peroxide is used together with thevinylsilane compound in order to promote the silane grafting reaction ofthe ethylene copolymer (A).

The peroxide includes organic peroxides, and specific examples includebenzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butylperoxide, 2,5-dimethyl-2,5-di(peroxide benzoate) hexyne-3,1,4-bis(t-butylperoxyisopropyl) benzene, lauroyl peroxide, t-butylperacetate, 2,5-dimethyl-2,5-di-(t-butylperoxide)hexyne-3,2,5-dimethyl-2,5-di(t-butylperoxide) hexane, t-butylperbenzoate, t-butyl perphenylacetate, t-butyl perisobutyrate,t-butylper-sec-octoate, t-butyl perpivalate, cumyl perpivalate, t-butylperdiethylacetate; azobisisobutyronitrile, dimethylazoisobutyrate etc.

Among these compounds, dialkyl peroxides such as dicumyl peroxide,di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di(t-butylperoxy) hexane and1,4-bis(t-butylperoxyisopropyl) benzene are preferably used.

The peroxide is used in an amount of usually 0.005 to 0.15 wt %,preferably 0.01 to 0.1 wt %, relative to the total (=100 wt %) of(A)+(B)+(C). In other words, the peroxide is used in an amount ofusually 0.005 to 0.15 part by weight, preferably 0.01 to 0.1 part byweight, relatiove to the total (=100 parts by weight) of (A)+(B)+(C).When the peroxide is used in this range, the reaction forsilane-grafting of the vinylsilane compound to the ethylene copolymer(A) can be suitably promoted.

[Metal Hydroxide (B)]

The metal hydroxide used in the present invention includes aluminumhydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide,manganese hydroxide, zinc hydroxide, hydrotalcite, and a mixturethereof, among which magnesium hydroxide or a mixture containingmagnesium hydroxide is particularly preferable.

[Graft Modified Ethylene Polymer (C)]

The ethylene polymer used as the material of the graft modified ethylenepolymer in the present invention is preferably an ethylene/α-olefincopolymer. The ethylene/α-olefin copolymer used as the material of thegraft modified ethylene polymer is preferably an ethylene/C3 to C10α-olefin copolymer. The C3 to C10 α-olefin is specifically propylene,1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene,3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene,4,4-dimethyl-1-pentene 4-ethyl-1-hexene, 1-octene, 3-ethyl-1-hexene,1-octene, 1-decene, etc. These may be used alone or in combination twoor more thereof. Among these olefins, at least one of propylene,1-butene, 1-hexene, and 1-octene is preferably used.

With respect to the content of each structural unit in the ethylenecopolymer, it is preferable that the content of a structural unitderived from ethylene is usually 75 to 95 mol %, preferably 80 to 95 mol%, and the content of a structural unit derived from at least onecompound selected from C3 to C10 α-olefins is usually 5 to 25 mol %,preferably 5 to 20 mol %.

The ethylene/α-olefin copolymer used in graft modification preferablyhas the following physical properties:

-   (i) the density is 855 to 910 kg/m³, preferably 857 to 890 kg/m³,-   (ii) the melt flow rate (MFR₂) under a loading of 2.16 kg at 190° C.    is in the range of 0.1 to 100 g/10 min., preferably 0.1 to 20 g/10    min.,-   (iii) the index (Mw/Mn) of molecular-weight distribution evaluated    by GPC is in the range of 1.5 to 3.5, preferably 1.5 to 3.0, more    preferably 1.8 to 2.5,    -   more preferably,-   (iv) the B value determined from ¹³C-NMR spectrum and the following    equation is 0.9 to 1.5, preferably 1.0 to 1.2;    B value=[POE]/(2·[PE][PO])    wherein [PE] is the molar fraction of a structural unit derived from    ethylene in the copolymer, [PO] is the molar fraction of a    structural unit derived from α-olefin in the copolymer, and [POE] is    the ratio of the number of ethylene/α-olefin chains to the number of    all dyad chains in the copolymer.

The ethylene/α-olefin copolymer used as the material of thegraft-modified ethylene polymer is preferably the one having the samecharacteristics as those described in the ethylene/α-olefin copolymerused in (A-1), but the comonomer species, density, molecular weight etc.of the copolymer may be the same as or different from those of (A-1).

The graft-modified ethylene polymer according to the present inventionis obtained by graft-modification of the ethylene copolymer with a vinylcompound having at least one kind of polar group. The vinyl compoundhaving a polar group includes vinyl compounds having oxygen-containinggroups such as acid, acid anhydride, ester, alcohol, epoxy and ether aspolar groups, vinyl compounds having nitrogen-containing groups such asisocyanate and amide, and vinyl compounds having silicon-containinggroups such as vinyl silane.

Among these compounds, vinyl compounds having oxygen-containing groupsare preferable, and unsaturated epoxy monomers, unsaturated carboxylicacids and derivatives are preferable.

The unsaturated epoxy monomers include unsaturated glycidyl ethers,unsaturated glycidyl esters (for example glycidyl methacrylate) etc.

Examples of the unsaturated carboxylic acids include acrylic acid,maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid,citraconic acid, crotonic acid, isocrotonic acid and nadic acid™(endo-cis-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid) etc.

Derivatives of the unsaturated carboxylic acids include, for example,acid halide compounds, amide compounds, imide compounds, acidanhydrides, and ester compounds of the unsaturated carboxylic acids.Specific examples include malenyl chloride, maleimide, maleic anhydride,citraconic anhydride, monomethyl maleate, dimethyl maleate, glycidylmaleate etc.

Among these compounds, unsaturated dicarboxylic acids or acid anhydridesthereof are preferable, and particularly maleic acid, nadic acid™ oracid anhydrides thereof are preferable. The graft position of theunsaturated carboxylic acid or its derivative grafted onto theunmodified ethylene copolymer is not particularly limited, and theunsaturated carboxylic acid or its derivative may be bound to anarbitrary carbon atom in the ethylene polymer constituting thegraft-modified ethylene polymer.

The graft-modified ethylene polymer (C) can be prepared byconventionally known methods, for example by the following methods.

-   (1) A method of graft copolymerization by melting the unmodified    ethylene polymer in an extruder and then adding unsaturated    carboxylic acid etc.-   (2) A method of graft copolymerization by dissolving the unmodified    ethylene polymer in a solvent and adding unsaturated carboxylic acid    etc.

In both methods, the graft reaction is conducted preferably in thepresence of a radical initiator for efficient graft copolymerization ofgraft monomers such as the unsaturated carboxylic acid etc.

An organic peroxide, an azo compound or the like is used as the radicalinitiator. Examples of the radical initiator include organic peroxidessuch as benzoyl peroxide, dichlorobenzoyl peroxide and dicumyl peroxide,and azo compounds such as azobisisobutyronitrile and dimethylazoisobutyrate. Preferably used among these are dialkyl peroxides suchas dicumyl peroxide, di-tert-butyl peroxide,2,5-dimethyl-2,5-di(tert-butylperoxy)hexyn-3,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and1,4-bis(tert-butylperoxyisopropyl) benzene.

The radical initiator is used in an amount of usually 0.001 to 1 part byweight, preferably 0.003 to 0.5 part by weight, more preferably 0.05 to0.3 part by weight, relative to 100 parts by weight of the unmodifiedethylene polymer.

The reaction temperature in the graft reaction using the radicalinitiator or in the graft reaction without using the radical initiatoris determined in the range of usually 60 to 350° C., preferably 150 to300° C.

[Other Additives]

The thermoplastic resin composition of the present invention can beblended if necessary with additives such as an antioxidant, a UVabsorber, a weatherability stabilizer, a heat stabilizer, an antistatic,a flame retardant, a pigment, a dye, a lubricant etc. in addition tothose described above. The amount of each additive may be determineddepending on the object. For example, when a flame retardant representedby silicone resin is used, it can be used usually in an amount of about0.1 to 10 parts by weight relative to 100 parts by weight of (A), (B)and (C) in total.

[Thermoplastic Resin Composition]

The content of each component in the thermoplastic resin composition ofthe present invention is as follows: The lower limit of the ethylenecopolymer (A) is 20 wt %, preferably 25 wt %, more preferably 30 wt %,and the upper limit is 64.9 wt %, preferably 60 wt %, more preferably59.9 wt %, still more preferably 55 wt %. The lower limit of the metalhydroxide (B) is 35 wt %, preferably 40 wt %, and the upper limit is 70wt %. The lower limit of the graft-modified ethylene polymer (C) is 0.1wt %, and the upper limit is 30 wt %, preferably 10 wt %, morepreferably 6 wt %. Specifically, the ethylene copolymer (A) is forexample 20 to 64.9 wt %, preferably 25 to 60 wt %, more preferably 30 to55 wt %, the metal hydroxide (B) is 35 to 70 wt %, preferably 40 to 70wt %, the graft-modified ethylene polymer (C) is 0.1 to 30 wt %,preferably 0.1 to 10 wt %, more preferably 0.1 to 6 wt % (it is assumedthat (A)+(B)+(C)=100 wt %).

When the total of (A), (B) and (C) is 100 parts by weight, it ispreferable in the present invention that triazine ring containingcompound (E) described later is added in an amount of 0.1 to 20 parts byweight, and polyhydric alcohol (F) is added in an amount of 0.1 to 20parts by weight. The triazine ring containing compound (E) is a compoundcontaining a triazine ring, and includes melamine, ammeline, melam,benzoguanamine, acetoguanamine, phthalodiguanamine, melamine cyanurate,pyrophosphoric melamine, butylene diguanamine, norbornane diguanamine,methylene dimelamine, ethylene dimelamine, trimethylene dimelamine,tetramethylene dimelamine, hexamethylene dimelamine, 1,3-hexylenedimelamine etc., among which melamine cyanurate is particularlypreferable.

The polyhydric alcohol (F) includes pentaerythritol, dipentaerythritol,tripentaerythritol, polypentaerythritol, trishydroxyethyl isocyanate,polyethylene glycol, glycerin, starch, glucose, cellulose, sorbitol etc.

When the weight ratio ((E)/(F)) of the triazine ring containing compound(E) to the polyhydric alcohol (F) is 1 or more, the flame retardanteffect is further improved.

The thermoplastic resin composition (Y) according to the presentinvention is prepared by melt-mixing the above-mentioned components (A),(B) and (C) and additives blended if necessary by a wide variety ofconventionally known methods.

The thermoplastic resin composition is obtained for example by mixingthe above components simultaneously or successively in a Henschel mixer,V-type blender, tumbler mixer, ribbon blender etc. and thenmelt-kneading the mixture by a single-screw extruder, multiple screwextruder, kneader, Banbury mixer etc.

When the multiple screw extruder, kneader or Banbury mixer particularlyexcellent in kneading performance is used, a high-quality polymercomposition wherein the respective components are dispersed moreuniformly can be obtained.

Further, the additives for example an oxidant etc. can be added ifnecessary in an arbitrary stage.

[Polymer Composition (Z)]

Then, the polymer composition (Z) according to the present invention isdescribed.

The polymer composition (Z) according to the present inventioncomprises:relative to

-   -   (AA) 100 parts by weight of at least one polymer selected from a        thermoplastic polymer (aa1) and a thermosetting polymer (aa2),        in the ratio of    -   (BB) 50 to 250 parts by weight of a metal hydroxide,    -   (E) 0.1 to 40 parts by weight of a triazine ring containing        compound, and    -   (F) 0.1 to 40 parts by weight of a polyhydric alcohol.

The polymer (AA) used in the polymer composition of the presentinvention is at least one kind of polymer selected from thermoplasticpolymer (aa1) and thermosetting polymer (aa2). These can be used aloneor as a blend of two or more thereof.

[Thermoplastic Polymer (aa1)]

The thermoplastic polymer includes olefin polymers such as ethylenepolymer, propylene polymer, polybutene, poly-4-methyl-1-pentene etc.;styrene block copolymers; polyvinyl acetate; acryl polymers such aspolyacrylate, polyacrylonitrile etc.; polyethers such as polyphenyleneoxide, polyethylene oxide etc.; polyesters such as PET etc.;polyurethane; polyamide; polyphenylene sulfide; ABS resin;polycarbonate; graft-modified olefin polymers etc. These can be usedalone or as a blend of two or more thereof. In particular, the ethylenepolymers and styrene block copolymers are preferable.

The ethylene polymers include an ethylene/α-olefin copolymer,ethylene/vinyl acetate copolymer, ethylene/ethyl acrylate copolymer,ethylene/methyl methacrylate copolymer, ethylene/acrylic acid copolymer,ethylene/methacrylic acid copolymer and ionomers thereof, anethylene/methacrylate copolymer, graft-modified ethylene/α-olefincopolymer etc. The structure of the molecule may be linear or may bebranched with a long or short chain. These polymers may be a mixturethereof with polyethylene.

The ethylene/α-olefin copolymer is an ethylene/α-olefin random copolymerwherein the α-olefin used as comonomer is C3 to C20, preferably C3 toc10, α-olefin. Examples of the α-olefin include propylene, 1-butene,1-pentene, 1-hexene, 4-methylpentene-1,1-octene, 1-decene, 1-dodecene,and a combination thereof, among which propylene, 1-butene, 1-hexene,and 1-octene are preferable. If necessary, other comonomers, for exampledienes such as 1,6-hexadiene, 1,8-octadiene, 5-ethylidene-2-norborneneand dicyclopentadiene, cyclic olefins such as cyclopentane, etc. may becontained in a small amount. The content of ethylene in the copolymer is30 to 99.9 (mol %), preferably 50 to 99.5 (mol %), more preferably 75 to99.5 (mol %).

The method of producing the ethylene polymer is not particularlylimited, and the ethylene polymer can be produced by homopolymerizationof ethylene or copolymerization of ethylene with α-olefin by using aradical polymerization catalyst, Philips catalyst, Ziegler-Nattacatalyst, or metallocene catalyst.

As the ethylene polymer used in the polymer composition (Z) of thepresent invention, an ethylene/α-olefin copolymer which can be used asthe component (A-1) in the thermoplastic resin composition (Y) ispreferably used.

The styrene block copolymer includes a styrene/butylene/styrene blockcopolymer, styrene/isoprene/styrene block copolymer,styrene/ethylene/butylene/styrene block copolymer,styrene/ethylene/propylene/styrene block copolymer,styrene/butadiene/styrene block copolymer and hydrogenated productsthereof.

[Thermosetting Polymer (aa2)]

The thermosetting polymer of the present invention includes phenolresin, urine resin, melamine resin, unsaturated polyester, epoxy resin,polyurethane, silicone resin etc. These can be used alone or as a blendof two or more thereof.

[Metal Hydroxide (BB)]

The metal hydroxide in the present invention includes aluminumhydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide,manganese hydroxide, zinc hydroxide, hydrotalcite etc. These metalhydroxides may be used alone or as a mixture thereof, and magnesiumhydroxide alone or a magnesium hydroxide-containing mixture isparticularly preferable.

[Triazine Ring Containing Compound (E)]

The triazine ring containing compound in the present invention is acompound containing a triazine ring, and includes melamine, ammeline,melam, benzoguanamine, acetoguanamine, phthalodiguanamine, melaminecyanurate, pyrophosphoric melamine, butylene diguanamine, norbornenediguanamine, methylene dimelamine, ethylene dimelamine, trimethylenedimelamine, tetramethylene dimelamine, hexamethylene dimelamine,1,3-hexylene dimelamine etc., among which melamine cyanurate isparticularly preferable.

[Polyhydric Alcohol (F)

The polyhydric alcohol in the present invention includespentaerythritol, dipentaerythritol, tripentaerythritol,polypentaerythritol, trishydroxyethyl isocyanate, polyethylene glycol,glycerin, starch, glucose, cellulose, sorbitol etc.

[Other Additives]

The polymer composition of the present invention can be blended ifnecessary with additives such as an antioxidant, a UV absorber, aweatherability stabilizer, a heat stabilizer, an antistatic, a flameretardant, a pigment, a dye, a lubricant etc. in addition to thosedescribed above.

[Polymer Composition]

The polymer composition (Z) of the present invention comprises relativeto (AA) 100 parts by weight of at least one polymer selected from athermoplastic polymer (aa1) and a thermosetting polymer (aa2), in theratio of (BB) 50 to 250 parts by weight, preferably 70 to 200 parts byweight of a metal hydroxide, (E) 0.1 to 40 parts by weight, preferably10 to 30 parts by weight of a triazine ring containing compound, and (F)0.1 to 40 parts by weight, preferably 10 to 30 parts by weight of apolyhydric alcohol.

When the weight ratio ((F)/(E)) of the polyhydric alcohol (F) to thetriazine ring containing compound (E) is 1 or more, the flame retardanteffect is further improved.

The polymer composition (Z) according to the present invention isprepared in various known methods by melt-mixing the above components(AA), (BB), (E) and (F) and additives blended if necessary.

The polymer composition according to the present invention is obtainedfor example by mixing the above components simultaneously orsuccessively in a Henschel mixer, V-type blender, tumbler mixer, ribbonblender etc. and then melt-kneading the mixture by a single-screwextruder, multiple screw extruder, kneader, Banbury mixer etc.

When the multiple screw extruder, kneader or Banbury mixer which isparticularly excellent in kneading performance is used, a high-qualitypolymer composition wherein the respective components are dispersed moreuniformly can be obtained.

Further, the additives for example an oxidant etc. can be added ifnecessary in an arbitrary stage.

[Molded Product Comprising the Thermoplastic Resin Composition (Y) orthe Polymer Composition (Z)]

The molded product of the present invention can be produced by formingthe thus obtained thermoplastic resin composition (Y) or the polymercomposition (Z) according to the present invention in various shapes byconventionally known melt-molding methods such as extrusion molding,rotational molding, calender molding, injection molding, compressionmolding, transfer molding, powder molding, blow molding and vacuummolding.

When the thermoplastic resin composition (Y) or the polymer composition(Z) according to the present invention is used in various applicationsfor example to a cover for electric wires, such as a sheath or aninsulating material for electric wires, the molded product of thepresent invention is a covering layer such as a sheath or an insulatingmaterial for electric wires, and this covering layer such as a sheath oran insulating material for electric wires is formed around an electricwire by a conventionally known method such as extrusion.

EXAMPLES

Hereinafter, the present invention is described in more detail byreference to the Examples, but the present invention is not limited tothe Examples.

Physical properties of the ethylene/α-olefin copolymer (A-1) andTafiner™ T A described later were evaluated in the following manner.

(1) Density

A strand after measurement of MFR at 190° C. under a loading of 2.16 kgwas heat-treated at 120° C. for 1 hour, then cooled over 1 hour to roomtemperature and measured by a density gradient tube method.

(2) α-Olefin Content, Tαβ/Tαα, B value

Determined by ¹³C-NMR spectrum.

(3) Intrinsic Viscosity [η]

Determined at 135° C. in decalin.

(4) Mw/Mn

Determined at 140° C. in an o-dichlorobenzene solvent by GPC (gelpermeation chromatography).

(5) MFR₁₀/MFR₂

MFR₁₀ at 190° C. under a loading of 10 kg and MFR₂ at 190° C. under aloading of 2.16 kg according to ASTMD-1238 were measured, and theMFR₁₀/MFR₂ ratio was calculated. A higher ratio indicates higherfluidity of the polymer upon melting, that is, higher processability.

Preparation of an insulating wire sample and evaluation thereof wereconducted by the following methods.

(6) Break Strength and Elongation at Break

According to JIS K6301, a tensile test was conducted by Dumbbell JIS No.3 with a span of 20 mm at a stress rate of 200 mm/min., to determinebreak strength and elongation at break.

(7) Torsional Rigidity

According to JISK6745, torsional rigidity at a temperature of 23° C. wasmeasured by using a Clash-Berg testing machine manufactured by ToyoSeiki.

(8) Scratch Resistance

Using a Martens scratch hardness testing machine manufactured by TokyoShoki, a test specimen of 3 mm in thickness was loaded with a tensileindenter of 20 g, then scratched, and measured for the width of a grooveoccurring upon scratching, and the reciprocal of the width wascalculated to determine scratch resistance. When the measurement was 11or more, ∘ was given; when the measurement was 10 to 11, Δ was given;and when the measurement was less than 10, x was given.

(9) Whitening on Bending

A test specimen of 2 mm in thickness was fixed at one end and then bentvertically an angle of at least 120° at a position apart by 3 cm fromthe other end, and whether whitening on bending occurred or not wasconfirmed with naked eyes. The sample not whitened was given o, and thewhitened sample was given x.

(Preparation of Ethylene/1-Butene Copolymer)

Production Example 1

(Preparation of Catalyst Solution)

0.63 mg bis(1,3-dimethylcyclopentadienyl) zirconium dichloride wasintroduced into a glass flask purged sufficiently with nitrogen, and1.57 ml methyl aminoxane in toluene (Al, 0.13 mM), and 2.43 ml toluenewere added thereto to give a catalyst solution.

(Preparation of Ethylene/1-Butene Copolymer a-1)

A stainless steel autoclave having an internal volume of 2 Lsufficiently purged with nitrogen was charged with 912 ml hexane and 200ml 1-butene, and the temperature in the system was increased to 80° C.Subsequently, 0.9 mmol triisobutyl aluminum and 2.0 ml of the catalystsolution prepared above (0.0005 mmol in terms of Zr) were injected withethylene to initiate polymerization. While the total pressure was keptat 8.0 kg/cm²-G by continuously feeding hydrogen at a rate of 70 ml/hr.and ethylene, the mixture was polymerized at 80° C. for 30 minutes.

After the polymerization was terminated by adding a small amount ofethanol into the system, the unreacted ethylene was purged. Theresulting polymer was poured into a large excess of methanol, wherebythe polymer was precipitated. This polymer was recovered by filtrationand dried overnight under reduced pressure, to give an ethylene/1-butenecopolymer. The states of the resulting ethylene/1-butene copolymer areshown in Table 1. TABLE 1 Ethylene 1-butene copolymer States of thepolymer a-1 Density (kg/m³) 885 Melt flow rate 1.2 Mw/Mn 2.0MFR₁₀/MFR_(2.16) 5.8

Production Example 2

(Preparation of Catalyst Solution)

18.4 mg of triphenyl carbenium (tetrakispentafluorophenyl) borate wasdissolved in 5 ml toluene to prepare a toluene solution at aconcentration of 0.004 mM/ml. 1.8 mg of [dimethyl(t-butylamide)(tetramethyl-η⁵-cyclopentadienyl)silane]titanium dichloride wasdissolved in 5 ml toluene to prepare a toluene solution at aconcentration of 0.001 mM/ml. At the time of polymerization, 0.38 mltoluene solution of triphenyl carbonium (tetrakispentafluorophenyl)borate and 0.38 ml toluene solution of [dimethyl(t-butylamide)(tetramethyl-η⁵-cyclopentadienyl) silane]titanium dichloride, were mixedwith 4.24 ml diluting toluene, to prepare 5 ml toluene solution oftriphenyl carbenium (tetrakispentafluorophenyl) borate at aconcentration of 0.002 mM/L in terms of B[dimethyl(t-butylamide)(tetramethyl-η⁵-cyclopentadienyl)silane]titaniumdichloride at 0.0005 mM/L in terms of Ti.

(Preparation of Ethylene/1-Butene Copolymer a-2)

750 ml heptane was introduced at 23° C. into a 1.5-L SUS autoclaveequipped with a stirring blade and purged sufficiently with nitrogen.This autoclave was charged under cooling on ice with 10 g 1-butene and120 ml hydrogen with a stirring blade. Then, the autoclave was heated to100° C., and further pressurized with ethylene such that the totalpressure was increased to 6 KG. When the internal pressure in theautoclave reached 6 KG, 1.0 ml of 1.0 mM triisobutyl aluminum (TIBA) inhexane was injected with nitrogen. Subsequently, 5 ml catalyst solutionprepared above was injected with nitrogen into the autoclave to initiatepolymerization. Thereafter, the temperature was regulated for 5 minutessuch that the inner temperature of the autoclave was 100° C., whileethylene was directly fed to attain a pressure of 6 kg. Five minutesafter the polymerization was initiated, 5 ml methanol was introduced bya pump into the autoclave to terminate the polymerization, and theautoclave was depressurized to the atmospheric pressure. 3 L methanolwas poured into the reaction solution under stirring. The resultingpolymer containing the solvent was dried at 130° C. for 13 hours at 600Torr, to give 10 g ethylene/butene copolymer a-2. The states of theresulting ethylene/1-butene copolymer are shown in Table 2. TABLE 2Production Example 2 Ethylene/1-butene Copolymer States of the polymera-2 Density (kg/m³) 885 Melt flow rate 1.2 Mw/Mn 2.1 MFR₁₀/MFR_(2.16)10.0 B value 1.1 Tαβ/Tαα 0.3(Preparation of Maleic Anhydride Graft Modified Ethylene/1-ButeneCopolymer)

Preparation Example 3

10 kg of the ethylene/1-butene copolymer, and a solution of 50 g maleicanhydride and 3 g di-tert-butyl peroxide dissolved in 50 g acetone, wereblended in a Henschel mixer.

Then, the blend thus obtained was introduced via a hopper into asingle-screw extruder having a screw diameter of 40 mm and a L/D ratioof 26, extruded into a strand at a resin temperature of 260° C. at athroughput of 6 kg/hr., then cooled with ice, and pelletized to give amaleic anhydride graft modified ethylene/1-butene copolymer.

From the resulting graft modified ethylene/1-butene copolymer, theunreacted maleic anhydride was extracted with acetone, and as a resultof measurement of the amount of the maleic anhydride graft in this graftmodified ethylene/1-butene copolymer, the amount of the graft was 0.43wt %.

Examples Y1-1, Y1-2, Y1-3, Y1-4 and Y2, Comparative Examples Y1-1, Y2-1and Y2-2

In Examples Y1-1, Y1-2, Y1-4 and Y2 and Comparative Examples Y1-1, Y2-1and Y2-2, the ethylene/1-butene copolymer a-2 prepared by theabove-described method was used as the ethylene copolymer (A); magnesiumhydroxide was used as the metal hydroxide; and as the graft modifiedethylene polymer of unsaturated carboxylic acid or a derivative thereof,modified ethylene polymers obtained by modifying, in the amount of thegraft described shown in Table 3, the unmodified copolymers andunmodified polyethylene described in Examples Y1-1, Y1-2, Y1-3, Y1-4 andY2 and Comparative Examples Y1-1, Y2-1 and Y2-2 were used, and thesematerials were blended in the amounts (wt %) shown in the table, andmelt-kneaded and pelletized at a resin temperature of 190° C. to givepellets of each thermoplastic resin composition. Physical properties ofthis thermoplastic resin composition were evaluated by the methodsdescribed above. The results are shown in Table 3.

The unmodified copolymers described in Examples Y1-1 and Y2 are theethylene/1-butene copolymer a-1 prepared by the method described above.The unmodified copolymer described in Example Y1-2 is theethylene/1-butene copolymer a-2 prepared by the method described above.TABLE 3 Compar- Compar- ative ative Comparative Example Example ExampleExample Example Example Example Example Y1-1 Y1-2 Y1-1 Y1-3 Y1-4 Y2 Y2-1Y2-2 (A-1) Type a-2 a-2 a-2 a-2 a-2 a-2 a-2 a-2 Ethylene/a-olefincopolymer Unmodified Type a-1 a-2 — — — a-1 — — copolymer as Content of1-butene mol % 12 12 — — — 12 — — material of Intrinsic viscosity dl/g1.5 1.5 — — — 1.5 — — modified Glass transition ° C. −50 −50 — — — −50 —— polymer (C) temperature Degree of % 10 10 — — — 10 — — crystallizationB value — 1.5 1.1 — — — 1.5 — — Density kg/m³ 885 885 — — — 885 — —Unmodified Density kg/m³ — — — 965 920 — 965 920 PE as material ofmodified polymer (C) (C) Modified Amount of wt % 0.5 0.5 — 0.5 0.5 0.50.5 0.5 polymer charged MAH (unmodified copolymer: 100 wt) Amount of wt% 0.43 0.44 — 0.43 0.43 0.43 0.43 0.43 graft MAH Composition A-1 wt % 3636 36 36 36 36 36 36 (B) Magnesium wt % 60 60 60 60 60 60 60 60hydroxide Silicone resin wt % 3 3  3 3 3 3 3 3 (C) Modified wt % 1 1 — 11 3 3 3 polymer Physical Break strength MPa 9 9  8 8 8 10 7 7 propertiesof Elongation at break % 700 710 700  620 640 630 550 570 composition(between gages) Torsional rigidity MPa 30 29 29 44 40 36 50 45 Scratchresistance ∘, Δ, x ∘ ∘ x ∘ ∘ ∘ ∘ ∘ Whitening on ∘, x ∘ ∘ x ∘ ∘ ∘ ∘ ∘bending

Examples Z1 to Z6, Comparative Examples Z1 to Z12

An ethylene copolymer (trade name: Tafiner™A-1085; density, 885 kg/m³;MFR at 190° C. under a loading of 2.16 kg: 1.2 g/10 min. produced byMitsui Chemicals), magnesium hydroxide, melamine cyanurate,pentaerythritol and zinc borate were blended in the weight parts shownin Table 4, and melt-kneaded and pelletized at a resin temperature of190° C. in a Banbury mixer, to give pellets of a polymer composition.

The polymer composition was applied to a thickness of 0.8 mm around aconductor (outer diameter: 1.35 mm) of 7 twisted soft copper yarns eachhaving a yarn stock diameter of 0.45 mm, at a dice temperature of 220°C. at a screw revolution of 30 rpm at a throughput of 1.6 to 1.8 kg/hrin a melt-extruder (Laboplast Mill manufactured by Toyo Seiki) having anelectric wire coating dice arranged therein, whereby an insulatingelectric wire sample having a diameter of 3.0 mm was obtained.

[Vertical Flame Test (VW-1)]

The flame retardancy of the resulting insulating covering on theinsulating wire sample was evaluated by the VW-1 vertical flame teststipulated in the above-mentioned UL standards. As shown in FIG. 1, theinsulating wire 2 of 17 inches in length was vertically arranged as thesample in chamber 1 in the test device, and a kraft paper 3 was stuck toa part apart by 13 inches from the lower end, and adsorbent cotton 4 wasplaced below the insulating electric wire 2.

Then, a burner 5 arranged before the insulating electric wire 2 wasignited, and the flame was allowed 5 times to approach, at an angle of70° for 15 seconds, a part apart by 3 inches from the lower end of theinsulating electric wire 2, as shown by the dotted line in FIG. 1, andafter approaching the flame each time, the time (sec.) elapsed until theflame spreading to the insulating covering was extinguished after theflame of the burner 5 was extinguished was determined, and the maximumflaming time was recorded.

Then, the above test was conducted 3 times, and a sample satisfying anyof the following conditions (1) to (3) was evaluated to be excellent inflame retardancy (passing the test), while a sample failing to satisfyany one of the conditions was evaluated to be inferior in flameretardancy (not passing the test): (1) the maximum flaming time in the 3measurements was 60 seconds or less, (2) the kraft paper 3 was notburned by the flame spreading from the insulating covering, and (3) theabsorbent cotton 4 did not burn by a dropped burning material. For therank of flame retardancy, a sample satisfying two of the above 3conditions was given (Δ), a sample satisfying one of the 3 conditionswas given (▴), and a sample satisfying none of the 3 conditions wasgiven (x). The results are shown in Table 4.

It can be expected that the sample failing to pass the test can pass thetest by increasing the thickness of the covering, depending on the rankof flame retardancy. Accordingly, the sample (Δ) can be expected to passthe test by slightly increasing the thickness of the covering, while thesamples (▴) and (x) should have a considerable thicker covering. TABLES4 Conductor: number of yarns in wire/yarn diameter (mm) = 7/0.45, outerdiameter = 1.35 mm, finishing diameter = 3.0 mm Comparative ComparativeComparative Comparative Comparative Comparative Comparative Exam-Example Example Example Example Example Example Example Example Exampleple Z1 Z2 Z3 Z4 Z5 Z6 Z7 Z1 Z2 Z3 A-1085 100 100 100 100 100 100 100 100100 100 Mg(OH)₂ 170 170 170 170 170 170 170 170 170 170 Melamine  10  30 30  40  30  20 cyanurate Pentaerythritol  10  30  20  30  40 Zincborate  10  10  30  30 Vertical flame not passing Not passing notpassing not passing not passing not passing not passing not passingpassing test (VW-1) the test the test the test the test the test thetest the test passing the test the test the test Rank of flame x x x x xx ▴ Δ — — retardancy Comparative Comparative Comparative ComparativeComparative Example Example Example Example Example Example ExampleExample Z8 Z9 Z10 Z11 Z12 Z4 Z5 Z6 A-1085 100 100 100 100 100 100 100100 Mg(OH)₂ 220 220 220 220 220 220 220 220 Melamine  30  30  15  10  5cyanurate Pentaerythritol  30  5  10  15 Zinc borate  30  30 Verticalflame not passing Not passing not passing not passing not passing Notpassing passing test (VW-1) the test the test the test the test the testpassing the the the test test test Rank of flame x ▴ ▴ ▴ ▴ Δ — —retardancy1) Unit: parts by weight2) In the Table, a blank column means that the corresponding componentwas not blended.

Examples Z7 to Z9, Comparative Examples Z13 to Z15

Tafiner™A-1085, magnesium hydroxide, melamine cyanurate, pentaerythritoland zinc borate were blended in the amounts (weight parts) shown inTable 5, and melt-kneaded and pelletized at a resin temperature of 190°C. in a Banbury mixer, to give pellets of a polymer composition.

The polymer composition was applied to a thickness of 1.0 mm around aconductor (outer diameter: 4.8 mm) of 7 twisted soft copper yarns havinga stock yarn diameter of 1.6 mm, at a dice temperature of 220° C. at ascrew revolution of 30 rpm at a throughput of 1.6 to 1.8 kg/hr in amelt-extruder (Laboplast Mill manufactured by Toyo Seiki) having anelectric wire coating dice arranged therein, whereby an insulatingelectric wire sample having a diameter of 6.8 mm was obtained. Theresulting sample was examined in the vertical flame test (VW-1) in thesame manner as described above. The results are shown in Table 5. TABLE5 Conductor: number of yarns in wire/diameter of yarn = 7/1.6, outerdiameter = 4.8 mm, finishing diameter = 6.8 mm Comparative ComparativeComparative Example Example Example Example Z13 Example Z14 Example Z15Z7 Z8 Z9 A-1085 100 100 100 100 100 100 Mg(OH)₂ 150 150 150 150 150 150Melamine  20  25  20  15 cyanurate Pentaerythritol  20  15  20  25 Zincborate  20  20  30 Vertical flame not passing not passing not passingnot passing passing the test (VW-1) the test the test the test passingthe test test the test Rank of flame x ▴ ▴ Δ — — retardancy1) Unit: parts by weight2) In the Table, a blank column shows that the corresponding componentwas not blended.

Industrial Applicability

According to the present invention, there can be provided athermoplastic resin composition (Y) showing excellent break strength andelongation at break, excellent in pliability and flexibility and alsoexcellent in scratch resistance and whitening on bending, as well as itsmolded product.

The thermoplastic resin composition (Y) according to the presentinvention has the above-described effect, and thus it is suitable forapplications to various molded products such as an electric wirecovering, tape, film, flame-retardant sheet, pipe, blow-molded productand flame-retardant wall paper, and particularly it is suitable forapplications to a covering with electric wires, such as an electric wiresheath and an insulating material for electric wires.

According to the present invention, there can be provided thepolymerization composition (Z) having a high flame retardant effect, aswell as its molded product.

The polymer composition (Z) of the present invention according to thepresent invention has the above-described effect, and thus it issuitable for applications to various molded products such as an electricwire covering, tape, film, sheet, pipe and blow-molded product, andparticularly it is suitable for applications to a covering with electricwires, such as an electric wire sheath and an insulating material forelectric wires.

1-10. (canceled)
 11. A thermoplastic resin composition (Y) comprisingthe following (A) to (C): (A) 20 to 64.9 wt % of an ethylene copolymercomprising (A-1) an ethylene/α-olefin copolymer comprising ethylene andC3 to C10 α-olefin and (A-2) an ethylene polymer other than (A-1) insuch a ratio that (A-1)/(A-2) is 20/80 to 100/0 by weight, (B) 35 to 70wt % of a metal hydroxide, and (C) 0.1 to 30 wt % of a graft-modifiedethylene polymer, wherein the graft-modified ethylene polymer (C) is agraft-modified product of unsaturated carboxylic acid or a derivativethereof wherein the amount of the graft is 0.01 to 10 wt %, and theethylene polymer before modification of the graft-modified ethylenepolymer is an ethylene/α-olefin copolymer comprising ethylene and C3 toC10 α-olefin, and the ethylene polymer before modification has thefollowing properties: (i) a density (ASTM D1505, 23° C.) in the range of857 to 890 kg/m³, (ii) a melt flow rate (MFR₂) (ASTM D1238, loading 2.16kg, 190° C.) under a loading of 2.16 kg at 190° C. in the range of 0.1to 20 g/10 min., and (iii) an index (Mw/Mn) of molecular-weightdistribution evaluated by GPC in the range of 1.5 to 3.5.
 12. Thethermoplastic resin composition (Y) according to claim 11, wherein theethylene/α-olefin copolymer (A-1) has the following properties: (i) adensity (ASTM D1505, 23° C.) in the range of 855 to 910 kg/m³, (ii) amelt flow rate (MFR₂) (ASTM D1238, loading 2.16 kg, 190° C.) under aloading of 2.16 kg at 190° C. in the range of 0.1 to 100 g/10 min., and(iii) an index (Mw/Mn) of molecular-weight distribution evaluated by GPCin the range of 1.5 to 3.5.
 13. A molded product comprising thethermoplastic resin composition (Y) according to claim
 11. 14. Themolded product according to claim 13 wherein the molded product is aninsulating material for electric wires.
 15. The molded product accordingto claim 13 wherein the molded product is a sheath for electric wires.16. A polymer composition (Z) comprising: (AA) 100 parts by weight of atleast one polymer selected from a thermoplastic polymer (aa1) and athermosetting polymer (aa2), (BB) 50 to 250 parts by weight of a metalhydroxide, (E) 0.1 to 40 parts by weight of a triazine ring containingcompound, and (F) 0.1 to 40 parts by weight of a polyhydric alcoholwherein the amounts of (BB), (E) and (F) are based on 100 parts byweight of (AA).
 17. The polymer composition (Z) according to claim 16,wherein the thermoplastic polymer (aa1) is an ethylene polymer.
 18. Thepolymer composition (Z) according to claim 20, wherein the weight ratioof the polyhydric alcohol (F) to the triazine ring containing compound(E) is in the range of the following relationship (1):(F)/(E)≧1  (1).
 19. A molded product comprising the polymer composition(Z) according to claim
 16. 20. The molded product according to claim 19wherein the molded product is an insulating material for electric wires.21. The molded product according to claim 19 wherein the molded productis a sheath for electric wires.